Co-Doping Characteristics of Si and Zn with Mg in P-Type GaN

The authors investigated the doping characteristics of Mg doped, Mg-Si co-doped, and Mg-Zn co-doped Gan films grown by metalorganic chemical vapor deposition. They have grown p-GaN film with a resistivity of 1.26 {center_dot} cm and a hole density of 4.3 x 10{sup 17} cm{sup {minus}3} by means of Mg-Si co-doping technique. The Mg-Si co-doping characteristic was also explained effectively by taking advantage of the concept of competitive adsorption between Mg and Si during the growth. For Mg-Zn co-doping, p-GaN showing a low electrical resistivity (0.7 {center_dot} cm) and a high hole concentration (8.5 x 10{sup 17} cm{sup {minus}3}) was successfully grown without the degradation of structural quality of the film. Besides, the measured specific contact resistance for Mg-Zn co-doped GaN film is 5.0 x 10{sup {minus}4} {center_dot} cm{sup 2}, which is lower value by one order of magnitude than that for only Mg doped GaN film (1.9 x 10{sup {minus}3} {center_dot} cm{sup 2}).